This invention relates generally to a process for producing building materials from paint sludge and in particular to a process for using raw paint sludge from paint booth operations in the manufacture of building materials such as asphalt, cement, concrete, mortar, and plaster.
Paint sludge poses a serious and expensive disposal problem for painting operations in manufacturing plants. When an object such as an automobile is painted in a booth, the excess paint is collected in a water curtain or in a water stream underneath floor grates beneath the paint booth. This material is known as paint sludge. Disposal of paint sludge is a problem of considerable complexity that faces paint booth operators. Currently available disposal technology is based upon the principles of incineration, chemical and physical treatment, and solidification. The resulting end product of such technology is typically used as landfill. However, the use of paint sludge for landfill has its limitations because of concerns for potential environmental hazards and the cost of special precautions needed to handle such waste materials.
There have been many attempts to use paint sludge for creating various useful byproducts rather than to dispose of it, in order to gain some value thus lowering the cost. All of these efforts involved processing, in most cases to dry powder, which resulted in cost penalties that severely limited commercial interest. For example, Soroushian et al U.S. Pat. No. 5,489,333 issued Feb. 6, 1996 suggests the use of dried paint sludge powder as a filler admixed in Portland Cement. St. Louis U.S. Pat. No. 5,573,587 issued Nov. 12, 1996 teaches mixing raw paint sludge with quicklime (CaO) to chemically dry the sludge, creating a powder of paint solids and slaked lime suitable as a component for use in mortar, cement, concrete and asphalt.
Processing of paint sludge is time consuming and costly. Accordingly, there is need for a simple process that effectively uses all of the paint sludge solids generated by a paint booth facility.
None of the forgoing references suggest using liquid paint sludge directly as a component in concrete and cement type building materials.